Modeling of a closed-loop controlled laser machining process with different control strategies

1994 ◽  
Author(s):  
Andreas Penz ◽  
Doris Leidinger ◽  
Dieter Schuoecker
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Machining Process ◽  
Laser Machining

Control Strategies for a Highly Loaded Biological Ammonia Elimination Process

1993 ◽  
Vol 28 (11-12) ◽  
pp. 531-538 ◽  
Author(s):  
B. Teichgräber
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Level Control ◽  
Sludge Dewatering ◽  
Loop Control ◽  
Reject Water ◽  
Line Measurement ◽  
Control Pattern ◽  
On Line ◽  
Treatment Facilities

A nitrification/denitrification process was applied to reject water treatment from sludge dewatering at Bottrop central sludge treatment facilities of the Emschergenossenschaft. On-line monitoring of influent and effluent turbidity, closed loop control of DO and pH, and on-line monitoring of nitrogen compounds were combined to a three level control pattern. Though on-line measurement of substrate and product showed substantial response time it could be used to operate nitrification/denitrification within process boundaries.

scholarly journals Influence of a closed-loop controlled laser metal wire deposition process of S Al 5356 on the quality of manufactured parts before and after subsequent machining

2021 ◽  
Author(s):  
Dina Becker ◽  
Steffen Boley ◽  
Rocco Eisseler ◽  
Thomas Stehle ◽  
Hans-Christian Möhring ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Closed Loop ◽  
Deposition Process ◽  
Metal Wire ◽  
Machining Process ◽  
Machining Processes ◽  
Initial State ◽  
Additive Process ◽  
Shape Accuracy ◽  
Loop Control

AbstractThis paper describes the interdependence of additive and subtractive manufacturing processes using the production of test components made from S Al 5356. To achieve the best possible part accuracy and a preferably small wall thickness already within the additive process, a closed loop process control was developed and applied. Subsequent machining processes were nonetheless required to give the components their final shape, but the amount of material in need of removal was minimised. The effort of minimising material removal strongly depended on the initial state of the component (wall thickness, wall thickness constancy, microstructure of the material and others) which was determined by the additive process. For this reason, knowledge of the correlations between generative parameters and component properties, as well as of the interdependency between the additive process and the subsequent machining process to tune the former to the latter was essential. To ascertain this behaviour, a suitable test part was designed to perform both additive processes using laser metal wire deposition with a closed loop control of the track height and subtractive processes using external and internal longitudinal turning with varied parameters. The so manufactured test parts were then used to qualify the material deposition and turning process by criteria like shape accuracy and surface quality.

scholarly journals A Review of Control Strategies in Closed-Loop Neuroprosthetic Systems

2016 ◽  
Vol 10 ◽  
Author(s):  
James Wright ◽  
Vaughan G. Macefield ◽  
André van Schaik ◽  
Jonathan C. Tapson
Keyword(s):  
Closed Loop ◽  
Control Strategies

The application of compound proportional resonant control strategy in multiple PV inverters system

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840098
Author(s):  
Yuan Li ◽  
Huifang Shen ◽  
Chao Xiong ◽  
Yaofei Han ◽  
Guofeng He
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Control Strategies ◽  
Integrated Control ◽  
Reference Signal ◽  
Loop Model ◽  
Harmonic Compensation ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Set Up

In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.

scholarly journals Singularly Perturbation Method Applied To Multivariable PID Controller Design

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Mashitah Che Razali ◽  
Norhaliza Abdul Wahab ◽  
P. Balaguer ◽  
M. F. Rahmat ◽  
Sharatul Izah Samsudin
Keyword(s):  
Perturbation Method ◽  
Pid Controller ◽  
Closed Loop ◽  
Controller Design ◽  
Control Strategies ◽  
High Reliability ◽  
Treatment Plant ◽  
Computation Time ◽  
Singularly Perturbed ◽  
Singularly Perturbation

Proportional integral derivative (PID) controllers are commonly used in process industries due to their simple structure and high reliability. Efficient tuning is one of the relevant issues of PID controller type. The tuning process always becomes a challenging matter especially for multivariable system and to obtain the best control tuning for different time scales system. This motivates the use of singularly perturbation method into the multivariable PID (MPID) controller designs. In this work, wastewater treatment plant and Newell and Lee evaporator were considered as system case studies. Four MPID control strategies, Davison, Penttinen-Koivo, Maciejowski, and Combined methods, were applied into the systems. The singularly perturbation method based on Naidu and Jian Niu algorithms was applied into MPID control design. It was found that the singularly perturbed system obtained by Naidu method was able to maintain the system characteristic and hence was applied into the design of MPID controllers. The closed loop performance and process interactions were analyzed. It is observed that less computation time is required for singularly perturbed MPID controller compared to the conventional MPID controller. The closed loop performance shows good transient responses, low steady state error, and less process interaction when using singularly perturbed MPID controller.

Operation and Control of the PBMR Demonstration Power Plant

2006 ◽  
Author(s):  
Petrus D. Kemp ◽  
Chris Nieuwoudt
Keyword(s):  
Power Plant ◽  
Transient Analysis ◽  
Power Plants ◽  
Closed Loop ◽  
Control Strategies ◽  
Power Conversion ◽  
Conversion Unit ◽  
Demonstration Plant ◽  
And Control ◽  
Direct Cycle

A large interest in High Temperature Gas-cooled Reactors (HTGR) has been shown in recent years. HTGR power plants show a number of advantages over existing technology including improved safety, modular design and high temperatures for process heat applications. HTGR plants with closed loop direct cycle power conversion units have unique transient responses which is different from existing nuclear plants as well as conventional non-nuclear power plants. The operation and control for a HTGR power plant therefore poses new and different challenges. This paper describes the modes of operation for the Pebble Bed Modular Reactor (PBMR) demonstration plant. The PBMR demonstration plant is an advanced helium-cooled, graphite-moderated HTGR consisting of a closed loop direct cycle power conversion unit. The use of transient analysis simulation makes it possible to develop effective control strategies and design controllers for use in the power conversion unit as well as the reactor. In addition to plant controllers the operator tasks and operational technical specifications can be developed and evaluated making use of transient analysis simulation of the plant together with the control system. The main challenges in the operation and control of the reactor and power conversion unit are highlighted with simulation results. Control strategies in different operating regions are shown and results for the power conversion unit start-up transition and the loss of the grid connection during power operation are presented.

Lyapunov Control Strategy for Thermoelectric Cooler Activating an Ice-Clamping System

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Alexandra Mironova ◽  
Paolo Mercorelli ◽  
Andreas Zedler
Keyword(s):  
Manufacturing Systems ◽  
Control Strategies ◽  
Industrial Applications ◽  
Machining Process ◽  
Free Form ◽  
Cooling Power ◽  
Machining Processes ◽  
Clamping System ◽  
Ice Strength ◽  
Free Form Surfaces

Deformation-free clamping plays an important role in manufacturing systems helping to ensure zero-defect production. The fixture of workpieces during machining processes poses challenges not only for microparts but also for thin-walled pieces or free-form surfaces in macromanufacturing. To address this challenge, a nontraditional adhesive technique, using frozen water to clamp, is introduced in this paper. By increasing the cooling power and thus reducing the temperature of the clamping plate, higher adhesive ice strength and, therefore, a safer clamping system during machining process, can be achieved. The objective of this investigation is to ensure a stable low temperature and to compensate for thermal disturbances. Thanks to their structural robustness, Lyapunov-based control strategies demonstrate an appropriate capability to achieve these results in real industrial applications. Model design of the clamping system as well as simulation and experimental results are shown and discussed.

Ultrafast laser machining: process optimization and applications

2021 ◽  
Author(s):  
Norman Hodgson ◽  
Albrecht Steinkopff ◽  
Sebastian Heming ◽  
Hortense Allegre ◽  
Hatim Haloui ◽  
...  
Keyword(s):  
Process Optimization ◽  
Ultrafast Laser ◽  
Machining Process ◽  
Laser Machining

Stability of a Class of Piezoelectric State-Switching Methods

2000 ◽  
Author(s):  
Andrew J. Kurdila ◽  
William W. Clark ◽  
Weijian Wang ◽  
Dwayne E. McDaniel
Keyword(s):  
Lyapunov Functions ◽  
Closed Loop ◽  
Control Strategies ◽  
Short Circuit ◽  
Open Circuit ◽  
Hybrid Dynamical Systems ◽  
Multiple Lyapunov Functions ◽  
Control Laws ◽  
State Switching ◽  
The Stability

Abstract Experimental and anecdotal evidences have shown that state-switched control strategies for piezoelectric actuators can be advantageous. However, most discussions of the stability of these systems has relied on heuristic, or physically motivated, arguments. In this paper, we show that recent open-circuit/short-circuit state-switching control laws can be viewed as hybrid dynamical systems of Witsenhausen type. Within this framework, the closed-loop stability of OC/SC switching is rigorously established using the method of multiple Lyapunov functions.

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